Fix calibrate for ServerPushJpegStream:
Fix calibrate for ServerPushJpegStream:

- Get window size and initial parameters from video size.

- Remove the video buffer flushing.

The buffer flushing relies on frame_pending which is broken by the new
ServerPushJpegStream.

oneminot/libcvd,oneminot/libcvd,oneminot/libcvd